Unitary SK_1 of semiramified graded and valued division algebras

Abstract

We prove formulas for the unitary SK_1 of a semiramified graded division algebra (or valued division algebra over a Henselian field) with a unitary involution. These formulas generalize earlier formulas of Yanchevskii, (and Platonov and Ershov for the nonunitary SK_1).Comment: 34 pages. Correction in References in v.